We report a 52-year old obese Indian female who underwent simultaneous TKA with standard operating protocol. Peri-operative mechanical and chemo-thromboprophylaxis was given with no evidence of DVT. Acute PE presented on 3^rd post-operative day with an episode of breathlessness, chest pain and desaturation. A positive computed tomographic pulmonary angiography (CTPA) and high D-dimer levels were conclusive. Management with therapeutic anticoagulant therapy was done. No late mortality occurred. Return to her activities of daily living with improved knee scores was the desired outcome.

Simultaneous TKA in patient with a high body mass index should receive prophylactic thromboprophylaxis. Pre-operative risk stratification in TKA with a high index of suspicion in postoperative period are necessary steps to identify and manage a potentially fatal acute PE.